Abstract: Bacteria and in particular pathogenic bacteria are treated in a manner which alters the bacteria's native level or activity of DNA methyltransferase (Dam). The alteration results in a change in the bacteria's native level of methylation of adenine in a GATC tetranucleotide which inhibits virulence of the bacteria. Thus, compounds which inhibit proliferation of bacteria are useful in treating bacterial infections.

Abstract: The present invention is directed towards methods of producing antibodies using an attenuated strain of pathogenic bacteria (e.g. Haemophilus, E. coli, and/or Salmonella) having non-reverting genetic mutations relative to the wild-type organism which alter activity of DNA adenine methylase (Dam). The invention further includes compositions comprised of the attenuated bacteria and methods using these compositions to elicit an immune response and immunize a subject with highly specific antibodies. The invention also provides methods producing antibodies to heterologous antigens which the attenuated bacteria are engineered to produce.

Abstract: Bacteria and in particular pathogenic bacteria are treated in a manner which alters the bacteria's native level or activity of DNA methyltransferase (Dam). The alteration results in a change in the bacteria's native level of methylation of adenine in a GATC tetranucleotide which inhibits virulence of the bacteria. Thus, compounds which inhibit proliferation of bacteria are useful in treating bacterial infections.

Abstract: Immunogenic compositions are disclosed which are comprised of bacteria which are pathogenic in their native state but which are rendered non-pathogenic in a manner which alters the native level or activity of DNA adenine methylase. The genome is also artificially engineered to express a heterologous antigen such as an immunogenic antigen of a virus, protozoa, parasite or fungi.

Abstract: The virulence of bacterial strains and in particular pathogenic bacteria which infect human is reduced by an agent which alters the bacteria's native level or activity of DNA methyltransferase (Dam). The agent causes an alteration in the bacteria's native level of methylation of adenine in a GATC tetranucleotide which inhibits virulence of the bacteria. Thus, compounds and formulations thereof which reduce bacterial virulence inhibit proliferation of bacteria and are useful in treating bacterial infections, particularly in humans.

Abstract: The present invention is directed towards an attenuated strain of pathogenic bacteria (e.g. Haemophilus, E. Coli, and/or Salmonella) having non-reverting genetic mutations relative to the wild-type organism which alter activity of DNA adenine methylase (Dam). The invention further includes compositions comprised of the attenuated bacteria and methods using these compositions to elicit an immune response to produce highly specific antibodies. The invention also provides methods for preparing vaccines as well as screening methods to identify agents which may have anti-bacterial activity.

Abstract: The present invention is directed towards compositions containing pathogenic bacteria (e.g. Haemophilus, E. Coli, and/or Salmonella) having non-reverting genetic mutations which alter activity of DNA adenine methylase (Dam) and methods using these compositions to elicit an immune response to produce highly specific antibodies. The invention also provides methods for preparing vaccines as well as screening methods to identify agents which may have anti-bacterial activity.